Need help on project components

Hi, i'm familiar with circuit board assembly and have a rough idea of what components do what, but when it comes to working out what components i need to string together to create the desired effect, I have absolutely no idea where to start!

Basically I want to make a little circuit to flash some lights on a car (12v) in a certain sequence (i.e. flash 2 lights, then the left one only, then the right one, then the 2 again) Now where do I start in designing what I need/how it goes together?

Is it going to be just a series of capacitors etc and a switch? or is it going to be involving programming chips etc?

I really would appreciate any help. I know this is very basic but please help!

Thanks in advance!

Hmmm... you could use a decade counter...
Here is a little something I put togethor, slightly mediorce but according to the simulation, it does the job.

R2 and R4 you would have to calculate to be in accordance with type of leds you are using, if you are using leds, if you are driving a relay make sure you include a flyback diode.

Ofcourse in the place of the signal generator (XFG1) you would need to include a timer circuit, which I have not shown.
If you would like some more delay before the sequence begins again, you can connect the RST of U1 to Q4/5/6/7 etc. according to how much delay you'd like.

David.

I've made a similar circuit as a telephone ringer simulator and used a 555 as the timebase.

Since you aren't too experienced with the electronics hardware, why not focus on doing it in software? At least you could probably learn that a bit more quickly. You could buy a simple AVR development board (there are many vendors selling simple application boards for less than $40 out there) and just program some of the uP outputs to do the flashing. This way, you will be spending a few evenings figuring out a simple program and then burning it into the AVR board. Then it is a simple matter of adding some solid state relays or similar interfacing switches to drive some lamps. Lights on a car take a lot of current.

Wow! thats a great answer, thanks for taking the time to do that.

It all seems abit 'much' just for making a couple of lights flash.

I need to find the simplest/cheapest way of doing this.

To explain what I want to achieve in more detail, I need to have a 12v input line(from the car battery), then to a push switch (not one that will stay 'on' once pressed) which will cause the above succession of flashes, then stop. Also it is normal bulbs (21 watts(i think!)), not LED's if it makes a difference.

What I had in my head was (see picture):

Where A would be some kind of component (capacitor?) to 'hold' the charge for say 1 second before releasing it, B would be one that held for 2 secs, C for 3 secs.

So pressing the switch would send the voltage first down '1' and light both the bulbs straight away, then after one second '2' will release its charge and light the left bulb, then 3 will release after, and finally 4 to light them both once more.

Also I thort that when the switch is pressed, what will allow only the right amount of electric to pass into the circuit so the sequence only completes once? as if the switch was held too long it would cause the first set of flashes to illuminate too long

So have I made up my own laws of physics here or is this way at all possible?

Thanks for the help guys!

p.s. what prog do you use to make those wiring diagrams?

well you can still use a 4017 decade counter IC, and use a 555 timer with a 1second pulse for the clk pin, and so pin 0 will operate for 1second, and then pin 1 & 2 can connect together to the light for 2seconds, and so on, each pin will stay on for 1second, so putting pins 1 & 2 together to the light will light for 2 seconds, for the lights you are using you will need to connect the ic outpus to a transistor or a relay to operate the higher current.

not LED's if it makes a difference.

Click to expand...

Yep... in terms of power consumption/handling, it makes a difference.

I'm afraid a simple Resistor-Capacitor type network won't work for what you want to do, they can be used to fade the interior cabin light if you wish, but that's about it.

I have re-drawn the circuit for you - again without the timer (sorry), but some research into that and you should be up and running. For a quick demonstration schematic I use a program called multisim (the one you see here), for more serious/complicated things I use a program called Altium DXP.

In terms of this solution, using the 4017, it is probably the most straight forward one. As RadioRon suggested, there are microcontroller methods available (zillions of them) if you want to play around with that.

Whichever method you choose, ensure that you choose relays that will be able to handle the current load of the globes.